Street sweepers include a rear brush which selectively is put in contact with a street and caused to rotate so as to sweep dirt from the street to a chain assembly which conveys the street dirt along an inclined surface, upwardly at an angle into a hopper.
A problem with prior art sweeper chain assemblies is that they are composed of many separate components, and are expensive to assemble. One prior art chain assembly includes a pair of parallel spaced apart straight sidebar chains. Each chain comprises a plurality of pairs of chain sidebars connected together by chain pins. Selected pairs of sidebars have flight attachments, extending away from each other, respectively including a surface normal to the rest of the sidebar. The flight attachments have bores extending therethrough, which bores have respective axes normal to the direction of chain travel. The axis of each bore through the flight attachments is mid way between chain pin holes of the associated sidebar. A planar, elongated, pusher bar or squeegee is sandwiched between two elongated angle irons and is bolted to the angle irons. One of the angle irons has spaced apart brackets which bolt to the flight attachments of the parallel spaced apart chains so that the pusher bar or squeegee extends perpendicularly to the direction of chain travel and is supported by the parallel spaced apart chain. Other pusher bars or squeegees are similarly mounted to other flight attachments so that there are a plurality of transversely extending flights secured to the parallel chains at selected sequential positions along the chains. The chain assembly conveys street dirt upwardly at an angle into a hopper.
Chains in street sweepers are operating in abrasive environments, and are subjected to wear.
A problem with using straight sidebar chains is that friction between chain pins and bushings causes elongation of such chains, resulting in sprocket teeth being jumped which causes skewing of the pusher bars extending between the parallel, spaced apart chains. Another problem with using straight sidebar chains is that wear at the interfaces of the bushing outer diameters and the sprocket tooth faces causes improper chain-sprocket interaction.